Explore topic-wise InterviewSolutions in .

Soaps are substances used with water, for cleaning and washing and are made from a compound of vegetable oils or animal fats along, with sodium or potassium hydroxide and generally have perfumes or colourants, added to it.

 Whereas 

Detergents are synthetic water soluble cleaning agents that unlike soap (which are prepared from vegetable oils or fats) are prepared from petroleum products along with sodium or potassium hydroxide.

  Detergents have an advantage over ordinary soap 

1. Hard water is one which does not lather with soap, while soft water lathers easily. 

2. Ordinary soap when rubbed in hard water is wasted and lather forms only after all the insoluble salts in hard water are removed as scum. 

3. Synthetic detergents do not form scum and lather even in hard water.

Burning of fossil fuels produces green house gases (CO, CO₂, water vapour, oxides of nitrogen, sulphur). High concentration of CO₂ causes global warming.

The main reasons to avoid the use of fossil fuels as sources of energy:

1. Fossil Fuels cause heavy environmental pollution on being combusted as they emit carbon dioxide and other pollutants in air. 

2. Fossil fuels are limited or finite in quantity and hence their use should be limited to save it for future. 

3. Incomplete combustion of fossil fuels causes liberation of carbon monoxide which is highly injurious to health.

(i) Force (newton) 

(ii) Work (joule) 

(iii) Volume

(B) Handheld (D) Data

Medicines are natural or synthetic substances which when taken in a living body, affects its functioning, and treats or prevents a disease. 

Aspirin 

Positive effect : 

1. It is a medicine to treat pain, fever and inflammation. 

2. Aspirin given shortly after a heart attack, may decrease risk of death. 

3. As long term use it may reduce, blood clots in people who are at a high risk. 

Negative effect : 

1. It is generally not recommended in children with infections. 

2. Its side effects may include upset stomach, stomach ulcers etc. 

Paracetamol 

1. It is a medicine to treat mild to moderate pain and fever. 

2. It may also be used in low back pain, headaches and for dental use. 

Negative effect : 

1. It maybe sold in combination with cold medications. 

2. It is safe at recommended doses, but too high a dose may result in liver problems.

Food processing – involves physical or chemical processes, to transform or change the raw ingredients in food into easy usable forms of food available in markets. Raw materials in food to Marketable food products .

(A) Green Computing

Various units used for describing measurement of various physical quantities: -

(i) CGS system 

(ii) FPS system 

(iii) MKS system 

(iv) SI system

Green Computing

The scientists who discovered 

(a) Atoms : John Dalton was a British chemist and physicist. He proved that matter consists of small indivisble called ‘atoms’. For this he proposed the atomic theory which was later on called “Dalton’s atomic theory”. 

(b) Oxygen : Joseph Priestly. 

(c) Safety lamp : Sir Humphry Davy. 

(d) Elements : Antoiene Lavoisier was a French nobleman. He revolutionized chemistry. Lavoisier named the elements carbon, hydrogen and oxygen and discovered the role of oxygen in combustion and respiration for which he is most noted. He established that water is a compound and helped to continue the transformation of chemistry from a qualitative science to a quantitative one.

 (i) Air pollution is caused by burning of fossil fuels.

(ii) CO₂ produced by burning fossil fuels produces greenhouse effect.

(iii) They are non-renewable sources of energy.

(iv) The oxides of carbon, nitrogen and sulphur that are released on burning fossil fuels are acidic oxides which lead to acid rain.

Towards the end of the 17th Century the scientific processes involving modem Chemistry started paving paths and Alchemy today is considered a pseudoscience and Chemistry regains its rightful position as a serious scientific field.

(A) Green Computing

Physical quantities and their measurements in chemistry

Mass – quantity of matter present in a substance.

Weight – force exerted by gravity on an object

Volume – the space occupied by a substance, or enclosed within a container

Density – mass per unit volume

Temperature – the degree or intensity of hotness of a substance

Pressure - force exerted per unit area on or against an objec

All medicines must be taken under proper doctors supervision and in the correct dose because some medicine has side effect as aspirin not taken in proper dose may cause stomach ulcers similarly paracetamol if taken in high dose may cause liver problems.

The woman in the Control Centre looked at the narrator strangely because the narrator asked him about the black aeroplane and she saw no one except the narrator’s plane in the sky during the storm. Even the radar showed only the narrator’s plane that night in the sky.

After landing, the narrator was not sorry to walk away from the old Dakota because he had a horrific and scary experience flying that plane. He was happy that he had landed the plane safely. That is why he was not sorry to walk away. Instead, he wanted to know where he was and who the other pilot 

i. Organic chemistry : 

It deals with properties and reactions of compounds of carbon. 

ii. Inorganic chemistry :

It deals with the study of all the compounds which are not organic. 

iii. Physical chemistry :

It deals with the study of properties of matter, the energy changes and the theories, laws and principles that explain the transformation of matter from one form to another. It also provides basic framework for all the other branches of chemistry.

Science is the subject which includes the study of various experiments performed by a scientist with all observations recorded and inferences concluded. 

Bifurcation : Science is bifurcated into three main branches Physics, Chemistry and Biology which make study of each branch simple and more focussed.

A huge storm was brewing up and the author was keen to reach his home to spend his holiday with his family. So, he decided to fly through the storm as he did not want to miss the chance to meet his family at breakfast.

Thus he took the risk even when the visibility was almost zero in the storm.

Yes, I had a similar experience while leaning to ride a bicycle in class V. In my initial attempts, I fell down every time and developed a fear of cycling which was .difficult to overcome.

No amount of provoking and cajoling could let me try it again, but my father encouraged me to overcome the fear and helped me as he was adamant on my learning cycling. He took me on a mound near village and made me sit and asked me to put my hands on the s handle and feet on the pedal. It sped down and I enjoyed it without fear which developed’ s my confidence.

Thus, I overcame my fear of cycling and started riding a cycle after a few practice.

(a) Inorganic chemistry includes study of innumerable elements and compounds

(b) Organic chemistry includes study of specific carbon compounds built up mainly of carbon and hydrogen

1.  Compounds include hydrocarbons e.g., Methane 

2. Acids include-acetic acid

Round bottom flask is preferred to flat bottom flask because in round bottom flask heat is uniformly distributed throughout on heating.

We face some problems in the initial stage while learning new skill. Due to the fear S of failure, we hesitate to perform a task or to do something new. In case of the seagull his parents cajoled him to fly. In the example, I have given in the answer of previous question, I was cajoled by my father to learn cycling. So, at that stage, I was to learn cycling as it was very important for me to overcome my fear.

(a) Glass test tube : It is used for heating chemicals and studying reactions in chemicals solution. 

(b) Hard glass boiling tube : It is resistant to chemicals and used for special purposes. It is made of pyrex. 

(c) Beaker : It is used for holding pouring and mixing solutions. 

(d) Round bottom flask : In preparation of gases, where heating is required. Since the flask is round bottomed, heat is uniformly distributed throughout on heating. 

(e) Retort : For carrying out distillation experiments which include distillation of acids.

A glass apparatus which measures liquid by sucking the liquid at one end upto the marked level and later pouring it out.

(C) Pipette

A long glass apparatus closed at one end used for collecting gases.

(B) Gas jar

The answer is (b) monoculture in the area

(i) Loss of biodiversity. 

(ii) Varied needs of the local people can no longer be met.

(iii) Degradation of soil.

Polyester is added to natural fibre cotton, to give terylene because this combination makes the fabric easy to clean and crease resistant.

Sacred groves are highly protected because of religious and cultural traditions. These are refuges for large number of rare and threatened plants. They are ecologically unique and biodiversity rich regions.

People participation in the management of forests can help in increasing forest produce as well as in their conservation. Participation of local people in the management of forest leads to the revival of degraded sal forest. In 1972, the West Bengal Forest Department formulated a novel scheme to revive the degraded sal forest by involving the local people. The forest officer A. K. Banerjee involved the villagers of the area around the forest in the protection of 1272 hectares of degraded Sal forest. In return for help in protecting the forest, the villagers were given employment in both silviculture and harvesting operations of the forest, 25 percent of the final harvest produce, and were allowed to collect firewood and fodder from the forest area on a nominal payment. With the active and willing participation of local people around the forest, the degraded sal forest of Arabari became thick and green within ten years.

 (i) In West Bengal the Sal forests had been very badly degraded.

(ii) A forest officer involved villagers protection of Sal forest and gave them employment in silviculture and harvesting operations. 

(iii) Villagers were allowed to collect firewood and fodder on a nominal payment.

(iv) Within a period of 10 years the previously worthless forests became valuable.

Saving of sal forest of Arabari in Midnapore District. 

Chipko Movement to protect the trees from cutting down in Reni village Garhwal.

(a) Clearing of forest land for agriculture. 

(b) Building of roads through forests. 

(c) Falling of large number of trees for furniture.

● The Chipko Andolan (Hug the Trees Movement) was the result of a grass root level effort to end the separate of people from their forests. 

● The movement originated from an incident in a remote village called Reni in Garhwal during the early 1970s. 

● There was a dispute between the local villagers and a contractor who had been allowed to cut trees in a forest close to the village. 

● On a particular day, the contractor’s workers appeared in the forest to cut the trees, seeing this the women of the village reached the forest quickly and clasped the tree trunks thus, preventing the workers from felling the trees. 

● The protest spread in that area, as a result, the contractor had to withdraw its plan to cut trees.

Quality of soil and sources of water.

True

Local people can effectively use forest resources without harming them, they have great knowledge of these resources. So active participation of local people leads to efficient management of forests.